When it was first unveiled in 2009, the four-door luxury sedan Porsche Panamera left many loyalists of the brand stunned. Not only had Porsche entered an entirely new segment of the market, but here was a four-door Porsche, a dramatic departure from the 911’s iconic sports car silhouette.

It was quite simply something unlike we’ve ever seen from the brand… although, this depends on who you talk to. While casual observers may know nothing about it, Porsche had already dabbled in four-door luxury sedans, 21 years earlier, to be precise. It was named the Porsche 989, a luxury car concept inspired by the sales success – at the time – of the front-engined 928. The luxury GT 928 combined the sharp dynamics of the 911 with a more lavish interior and increased refinement, and in the late 1980’s, Porsche first put forward the idea of a four-door luxury car, to be known as the 989, to further build upon the success of the 928 formula.

Unfortunately, the global economy had other plans and the early 90’s recession hit. Add to this the departure of Dr. Ulrich Bez – engineer at Porsche at the time and the creator of the 989 – and the once promising future of the most revolutionary Porsche model seemed doomed. A great pity, since the oily bits seemed destined for greatness; it featured a front-engine, rear-drive platform and a 300 hp V8 engine. With its development still in progress, Bez left Porsche in 1991, which was also around about the time that 928 sales slowed. The result of all this instability? The 989 project was binned, and since then it has been kept well under wraps.

It doesn’t take an enthusiast to see that the 989, even only in prototype form, is the spiritual predecessor to the Panamera. Although much more delicate in its design, the 989 featured a similarly bulbous rear-end to the Panamera, while the rear seating is also sculpted for two. What the 989 didn’t feature was seating that was as generous or the same design accommodations – due to the more primitive safety standards at the time – for crash safety. It was very much a 911 with two extra doors as subtly added on as possible. However, both cars feature the rear door opening halfway across the rear wheel arch as well as a roofline that is clearly part of the same family.

Although Porsche has kept the 989 fairly well hidden, last year the Porsche Museum in Stuttgart ran an exhibition of many of its top-secret concept cars and prototypes, which opened to the public for a limited period. If you’ve never seen the 989, take a glimpse of what might have been here.

With Porsche not known for its failures or blunders, one must assume that ditching the 989 after so many years of development must have hurt. So much, in fact, that the company never entirely gave up on the idea of a four-door luxury sedan. The 989 simply found itself in the right place at the wrong time.

Although it took another two decades, Porsche finally brought to the market the hugely capable Panamera and although sales have declined since its peak in 2012, nearly 20 000 of these luxury sedans found homes last year. Honoring Bez’s desire for the 989 to offer luxurious accommodation and superior dynamic performance to its German rivals, the Panamera remains a formidable feat of engineering and will take up a significant chapter in the Porsche history book.